Importance

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Abstract

Methods and systems for effectuating simultaneous transmission of a standard analog television video signal and a data signal. A transmitter system comprises an analog video signal path and a data signal path. The data signal path produces a data signal that is added to, combined with, or otherwise imposed on the video signal, so as to be substantially in quadrature with the video signal as sensed by television receivers in the broadcast region. An abatement signal is generated and applied to the video signal in order to correct for effects of the data on the video signal. The abatement signal is generated based on feedback control metric signals obtained from receiver emulation which uses as input a signal corresponding to the television signal as transmitted. The feedback control metric signals can also used to control the modulation of the data, for example, by adjusting the interpolation of the data based on the amplitude and frequency responses of the data signal. The transmitter system also comprises a subsystem which produces phase and amplitude correction signals for compensating for non-linear distortions in the transmitter system. The metrics can also be used in combination with a reference path to control timing of the data signal as applied to the video signal for output to the transmitter. Receivers according to various embodiments of the present invention separate the data from the video signal, do appropriate processing on the data signal in order to extract and recover the data, and forward the data for output. Such receivers can also include or contain, if desired, output to television receivers for rendering television programming.

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First Claim